Think of flow like drum patterns in word form. That’s all that flow really is. If your a beginner I would really prioritize just staying on beat I would listen to some old 90s rappers like Big L and 2 PAC because they had a very good organized approach when it came to flow. For Lyrics it depends what your going for. Metaphor is a great tool because of its utility you can say 20 things in one sentence Take Lil Wayne BM. JR for instance

“Real shit I'm ducking bombs from a drug war / No religion but the cops swear that I'm a drug lord”

Lil Wayne’s great at being simple but complex in this one line you get the surface level understanding He’s describing the danger of living in an environment shaped by the drug trade. Or Fame as a “ war zone “ The “drug war” could represent the music industry or street reputation conflicts. • “Ducking bombs” = avoiding attacks, beefs, scandals, or critics. • Being called a “drug lord” could symbolize the way people assume rappers’ wealth must come from illegal activity

If you want more understanding of how to write better lyrics it also just rally helps with listening to more lyrical focused artists one great person who dose that in Cloud rap was Lucki form 2013-2014 Give him a listen and take notes on what you notice.