Genki 1 feels like a fairly gentle introduction to Japanese. It also has a ton of exercises. I did Genki 1 and 2 after dabbling a lot in other resources, including the JapanesePod101 courses (also fairly decent as a starting point, because they’re quite slow-paced and fun).
Tae Kim’s guide is good, but kind of assumes one has some basics, because it tends to be technical at times: http://www.guidetojapanese.org/learn/http://www.guidetojapanese.org/learn/
If you have questions regarding grammar or vocab, feel free to check these threads: