I also had difficulty searching for maps as a beginner, so I'll try to help the best I can.
My way to get lots of beatmaps was searching on youtube. You can search for "x number" beatmap packs and get them easily. The video usually has a zip file, just unzip it into your songs folder. You can even search for specific styles of maps.
Another option is to go to osu's beatmap packs website. Go ham and download a lot of them to get a big library of beatmaps to play.
There is a website called osu!collector which has lots of beatmap packs compiled by users. You can sort by difficulty, style, and more.
If you check the pinned posts in this forum, there is a post containing lots of torrents for beatmap packs. I downloaded like 5 of them and got plenty of maps to play. There are even map packs for multiple modes.
Check out this playlist for beatmap pack downloads :
https://www.youtube.com/watch?v=qUMxfnE48fs&list=PLojXk58RKpj0JXhmaPpwoYdYQlizzRsKpI think I downloaded the 1000 beatmap pack from this guy, the maps are varied in difficulty and style of mapping.
Unfortunately, map collecting can be a bit annoying when starting off. My last suggestion is to just keep playing, looking on osu's beatmap search, and maybe even join multiplayer lobbies to play new beatmaps selected by others.