What to delete/format?

Hopefully someone else can assist you.

You cannot install windows on the drive you are attempting to in the screenshot posted 3GB is not enough space - I believe the absolute minimum is around 32GB though I normally allocate at least a 128GB Drive, (ssd), but these days I go with a 256GB drive (SSD).

I would suggest you back-up any data you wish to keep and wipe the disk completely and install to a totally clean system and let windows sort things out as part of the install, It will allocate and create at least two partition, a System Reserved and an OS partition. The OS partition will be the size of the disk minus 500 MB for the System Reserved partition, ( used for boot and recovery systems ). Once you have the system running you can shrink the OS partition to a suitable size, 128 - to 256GB, and create a data partition with the released space

If the system came with Linux loaded any drivers included will be useless to a windows installation, they are totally incompatible. What you should do is research that all the windows drivers are available for your system, and it is fully compatible with the version of Windows 10 you intend to install. You will need to go to the manufacturer of your system's site and check what OS's they support for that specific system. If they only support Ubuntu then is is very unlikely that you will be able to run Windows on it

Once you are sure that the system will run windows - then you should wipe the disk completely and start the install, I would advise that you download and store a copy of as many drivers as you can find on a USB stick, this especially applies to the network drivers. If you can connect to the internet by an Ethernet cable for the install this will normally speed things up as windows can check for updates and drivers, and check the key and activate the system during the install