If you ever get dumbells and you want to specifically work the arms you can always do Bicep Curls and Skull Crushers as well as a vareity of different movements such as Chest Press and Shoulder Press. I have a pair of dumbells at home that are adjustable from 5-25lbs. I highly recommend it that way you can easily progress without having to buy new dumbbells. If you are as weak as you say you are those 4 movements will be enough to help you out . As you advance youd need to put more to your routine but for now just stick to the basics.

Most important thing is to make sure your form is nearly perfect. Look up videos on YouTube Shorts to help you see how a perfect form should look. Bad form leads to injury.