Need help help to memorise information.

Im a katarina otp and im trying to get better with her like when to roam/trade/farm in each match up but problem i have is when im watching guides or vods on YouTube im very short attention span so I get lost/bored and move onto something else, and with this im struggling to maintain this information. Has anyone else got this problem and can help me understand better on how to memorise things. Thanks in advance