You need to point your domain name to your hosting account, to make it available to your web visitors. This means that you need to update your domain nameservers.
Note: after you update the nameservers for your domain, it may take up to 1-2 days until your domain becomes operative. This period of time is called DNS propagation.
This process is not so complicated, so here is a step by step tutorial:
1. Login to your Namecheap account and click on Dashboard
2. Identify the domain that you would like to point to your SiteGround hosting. Go ahead and click on Manage
3. Scroll down to Nameservers section. Select the Custom DNS option from the drop down menu.
4. Now go to your SiteGround acount. Login and access the Websites area. Click on 3 dots located beside WordPress kit button and select the Server details option. Here you’ll see your NS1 and NS2 values. Copy both values.
5. Go back to your Namecheap account and paste both NS1 and NS2 values in your Custom DNS fields. Click on Save.
Now you’ll have to wait until the DNS propagation is complete. It may take up to 1-2 days, but most of the times it happens faster, in a matter of a few hours.
Meanwhile, you can install WordPress in your hosting account and check your site periodically to see if it’s live.
Once the DNS propagation is complete, you’ll be able to access and see your live website.