Took a semester of Japanese and now want to continue, want to know my options

Hi all. So, I took a semester of Japanese back in 2016. It taught me all of hiragana, katakana, and some kanji. I wanted to take the next course, but my class schedule overlapped that semester with a required class so I could not. Wondering how I should continue. I still have all of my notes from that semester, so I can still review those, but when it comes to continuing and learning more kanji and more sentences and talking, how should I best proceed? Should I use an app like Duolingo or LingoDeer? I graduated, so I obviously just can’t take the 102 course. Any advice would be appreciated!