This topic might be difficult to explain in the forum depending on your it knowledge and what you have done already.
But let's assume that both devices have the same operating system and it is Windows10 (is this correct?)
Open the Start menu and type in "Homegroup". I assume that you do not have a existing home group so follow the steps to create a new home group. During these steps you will receive a password. Note down the password.
Then open the same menu on PC and click on Join Now / Join Homegroup. Follow these steps. You should find the homegroup so that you can enter the password.
After these steps you should be able to see the other notebook/pc within the Explorer in the left menu.