HI sallen, the installation process is the same on a brand new drive. A lot of times, what I will do is to allow it to auto-configure the partitions. A lot of times it will give you 2GB swap space and dedicate everything else to root. The only time that this would be an issue is for a distro (non-Manjaro) that is trying to install your home partition separately. Personally, I don't like it doing this as then I have to worry about running out of space on my home partition. However, other's view it as useful because if something were to ever happen to the distro, it would be easy to recover and essentially just reinstall your OS without any problem. Kind of like a backup.
Anyway, I was able to find a pretty good beginner's guide on getting everything going. The video may be for an older version of Manjaro. However, this guide on the Manjaro forums is kept pretty much up to date. It is for an older version, however the installer that they are showing hasn't changed at all since the guide was made, so should still be good.https://wiki.manjaro.org/index.php?title=Graphical_Installation_Guide_for_Beginners_0.8.8
There are a few different installers available depending on the one you would like to use. The installer shown in the guide seems to work for the most part. Never personally have experienced an issue with it. Although, you have another (can't remember the name) that resembles the Ubuntu installer and finally CLI which is strictly command line with a minimal UI. Just depends on what you are comfortable using.
Let us know if you have any questions.