Hi Dashmoon,
Welcome to Webflow and the Webflow community.
Webflow is such a great and powerful tool, but it can be a bit of a learning curve too, and thus frustrations also come.
You’ve done the right thing to reach out to the community, stick with it.
Looking at your settings for ‘Project tt’ element, it appears you have set it to flex / horizontal (hence the left and right only when trying to add another div)
If you set that ‘Project tt’ element to inline Block
You should be able to insert the new div as you want.
Hope that helps,
Keiran