how do u clean ur print bed cause my prints keep going crazy and turning into spaghetti

#PrintClinic i have no idea what’s going on I was printing something and i had 5 peices 2 prited great the rest spaghettified and i have no idea what happend

I just made my first model and i just want to say i hope u like it if you print it it would make my day if you did

First model ever pls enjoy and tell me if anything goes wrong ^-^

I want ask a big question what do yall use for make you designs and since im a beginner i would like some good tips for modeling, and how do you orint your design, like how do you take your design on another platform and move to printing it on your printer? also how will i know how much filamint ill use on a design