I have been a member of BoonEx for 12 years using Dolphin. I took a break for a couple years and then decided to come back and start again. When I did, I chose to go with UNA and here is my suggestions/comments for you:

Before you even downloaded the software, you should have already known the following:

- Site Name/Domain registered
- Exactly what your site is about and how you want it to function - Be creative and unique
- Who your audience will be for targeting/getting new members (goes along with what you site is about)
- Even the Design/Layout (colors, banners, logos, etc.)
After installing UNA, I would strongly suggest you spend some time in the Studio before doing anything else. This is the place where any changes you want to make to your site will happen. Click everything and learn where everything is at. Don't be scared :) I did not find it that difficult to learn my way around at all. 

Do not set your expectations too high. We all would like to think we will be the next Facebook, Twitter, or Instagram but in reality, that will probably never happen. For most, having a site with 20-50 "active" members who enjoy your site, visit often and participate can be considered a 'successful website'.

UNA is new and unique so yes, it's different than Joomla, Wordpress, or any other CMS for that matter. To think that UNA needs 100's or 1,000's of modules/extensions to be a successful platform is really not true. Take Facebook or Twitter as example. The reason these 'giant' sites are so successful is because they are simple and direct. 99% of the members there use the site to do just a few things - Post content, like, share, and comment with friends/followers.. That's it! They can login to these sites and do exactly that in just a few clicks and they are done. The Timeline module in UNA can do all of that. Keep that in mind when building your own site. If you think having a site with a bunch of modules installed is going to make your site successful, you may be disappointed. Keep your site simple, direct, user friendly, and focused on 'what' you site is about, nothing more. 

Installing apps/modules within UNA is pretty simple also and can be done in just a few clicks. From the Studio Apps Market, find the app you want, click download, go to downloads, and click install. BAM! Done! Choose only the apps you need for you site's objective. 

The UNA community is still growing but, if you need help or looking for a specific module (custom), just post it in the discussions.