added how to search chapter

docs/HowTo/HowToSearch.md

+# How to search with Elasticsearch DSL
+
+In this chapter we will take a look how to perform a search via objective way with Elasticsearch DSL. Well, the good news is that is very simple. That's why we created this library ;).
+
+To start a search you have to create a `Search` object.
+
+```php
+$search = new Search();
+```
+
+> We won't include namespaces in any examples. Don't worry all class's names are unique, so any IDE editor should autocomplete and include it for you ;).
+
+So, when we have a `Search` object we can start add something to it. Usually you will add `Query`, `Filter` and `Aggregation`.
+
+> More info how create [queries](../Query/index.md), [filters](../Filter/index.md) and [aggregations](../Aggregation/index.md) objects.
+
+### Form a Query
+
+Lets take a simple query example with `MatchAllQuery`.
+
+```php
+$matchAllQuery = new MatchAllQuery();
+```
+
+To add query to the `Search` simply call `addQuery` function.
+
+```php
+$search->addQuery($matchAllQuery);
+```
+
+At the end it will form this query:
+
+```JSON
+{
+  "query": {
+      "match_all": {}
+  }
+}
+```
+
+
+> There is no limits to add queries or filters or anything.
+
+### Form a Filter
+
+To add a filter is the same way like a query. First, lets create some `Filter` object.
+
+```php
+$matchAllFilter = new MatchAllFilter();
+```
+
+And simply add to the `Search`:
+
+```php
+$search->addFilter($matchAllFilter);
+```
+
+Unlike `Query`, when we add a `Filter` with our DSL library it will add a query and all necessary stuff for you. So when we add one filter we will get this query:
+
+```JSON
+{
+  "query": {
+      "filtered": {
+          "filter": {
+              "match_all": {}
+          }
+      }
+  }
+}
+```
+
+### Multpile queries and filters
+
+As you know there is possible to use multiple filters and queries in elasticsearch. No problem, if you have several filters just add it to the search. `ElasticsearchDSL` will form a `Bool` query or filter for you when you add more than one.
+
+Lets take an example with `Query`:
+
+```php
+$search = new Search();
+$termQueryForTag1 = new TermQuery("tag", "wow");
+$termQueryForTag2 = new TermQuery("tag", "elasticsearch");
+$termQueryForTag3 = new TermQuery("tag", "dsl");
+
+$search->addQuery($termQueryForTag1);
+$search->addQuery($termQueryForTag2);
+$search->addQuery($termQueryForTag3, BoolQuery::SHOULD);
+```
+The query will look like:
+
+```JSON
+{
+  "query": {
+    "bool": {
+        "must": [
+            {
+                "term": { "tag": "wow" }
+            },
+            {
+                "term": { "tag": "elasticsearch" }
+            }
+        ]
+        "should": [
+            {
+                "term": { "tag": "dsl" }
+            }
+        ]
+    }
+  }
+}
+```
+> More info how to form bool queries find in [Bool Query](../Query/Bool.md) chapter.
+
+The same way it works with a `Filter`. Take a look at this example:
+
+```php
+$search = new Search();
+$termFilter = new TermFilter('name', 'ongr');
+$missingFilter = new MissingFilter('disabled');
+$existsFilter = new ExistsFilter('tag');
+$search->addFilter($termFilter);
+$search->addFilter($missingFilter);
+$search->addFilter($existsFilter, BoolFilter::MUST_NOT);
+```
+
+Elasticsearch DSL will form this query:
+
+```JSON
+{
+  "query": {
+    "filtered": {
+        "filter": {
+            "bool": {
+                "must": [
+                    {
+                        "term": {
+                            "name": "ongr"
+                        }
+                    },
+                    {
+                        "missing": {
+                            "field": "disabled"
+                        }
+                    }
+                ],
+                "must_not": [
+                    {
+                        "exists": {
+                            "field": "tag"
+                        }
+                    }
+                ]
+            }
+        }
+    }
+  }
+}
+```
+
+### Modify queries
+
+
+
+
+### Sent request to the elasticsearch
+And finaly we can pass it to `elasticsearch-php` client. To generate an array for the client we call `toArray()` function.
+
+```php
+//from elasticsearch/elasticsearch package
+$client = new Elasticsearch\Client();
+
+$searchParams = [
+  'index' => 'people',
+  'type' => 'person',
+  'body' => $search->toArray(),
+];
+
+$docs = $client->search($searchParams);
+```
+
+> This example is for elasticsearch/elasticsearch ~1.0 version.