As @xidnpnlss said, you have to first consider separately the different modules in OT.
Taking a part of the manual and practicing on it might be a good thing.
There is a thing about OT that made things difficult to me: the words employed for the different aspects were a bit confusing to me.
Merlin’s guide was an excellent document to make these concepts clearer to me.
IMHO some reading before and while practicing is key, you just can’t avoid it with OT.
@Olaf_Wolkenhauer made a big work to gather info about OT. Worth reading as well.