Create Sitecore Item from Existing template - sitecore

Question

I am new to sitecore, when I try to create new item for existing template. I am unable to call my master database.Need some guide for how to create new item in sitecore and how to show it on my running sitecore page? Just need some hint regarding flow of after creation how to render it on existing sitecore page.
<configuration type="Sitecore.Search.SearchConfiguration, Sitecore.Kernel" singleInstance="true">
<indexes hint="list:AddIndex">
<index id="system" type="Sitecore.Search.Index, Sitecore.Kernel">
<param desc="name">$(id)</param>
<param desc="folder">__system</param>
<Analyzer ref="search/analyzer" />
<locations hint="list:AddCrawler">
<core type="Sitecore.Search.Crawlers.DatabaseCrawler,Sitecore.Kernel">
<Database>core</Database>
<Root>/sitecore/content</Root>
<include hint="list:IncludeTemplate">
<application>{EB06CEC0-5E2D-4DC4-875B-01ADCC577D13}</application>
</include>
<Tags>application</Tags>
<Boost>2.0</Boost>
</core>
<core-controlpanel type="Sitecore.Search.Crawlers.DatabaseCrawler,Sitecore.Kernel">
<Database>core</Database>
<Root>/sitecore/content/applications/control panel</Root>
<include hint="list:IncludeTemplate">
<taskoption>{BDB6FA46-2F76-4BDE-8138-52B56C2FC47E}</taskoption>
</include>
<Tags>taskoption</Tags>
<Boost>1.9</Boost>
</core-controlpanel>
<master type="Sitecore.Search.Crawlers.DatabaseCrawler, Sitecore.Kernel">
<Database>master</Database>
<Tags>master content</Tags>
</master>
</locations>
</index>
</indexes>
</configuration>

Answer 1

I will write the code I usually execute:
Database database = Database.GetDatabase("master");
Item rooItem = database.GetItem(new ID(parentItemId));
if (rootItem == null) return null;
TemplateID pageTemplateId = new TemplateID(new ID(templateId));
string validName = ItemUtil.ProposeValidItemName(name);
using (new Sitecore.SecurityModel.SecurityDisabler())
{
Item newItem = rootItem.Add(validName, pageTemplateId);
if (newItem == null) return null;
//TODO: publish item
}
rootItem could be the home item
templateId will be the id of your page template (remember this page should have layout and renderings defined)