1. Where is the MPGH shop where I can buy name changes, profile picture size increase, etc? Link pls
You can get a name change via Profile Edit Requests.
You will need to meet the requirements in order for you to get the name change.
For profile picture/avatar size increase, you will need to upgrade yourself to the following usergroups.
Donator is your best option. All you have to do is donate a minimum of $25 USD to MPGH.
2. Why can't I post links? What must I do to be able to post links?
You cannot post links if you do not have the Member Level 1 Tag.
You can post links now, since you have the tag. For more information, please visit this link.
3. How to get a signature?
You can get a signature by clicking the settings button and then click edit signature. (I have attached the links for you)
4. How do I join a group, can't seem to find the "join" button. I want cool usergroups
As for groups, you can find tons of them through this link.
You can also Join Groups via the "Join Group" button through your own profile.
As for usergroups, you will have to earn your way up.