Well best bet is search U tube a picture is worth a thousand words, but here are my words for what it’s worth.
Turn the water off, better say that just in case!
Unscrew the top knurled (the textured grip above the head, part you turn) rings that are marked hot or cold. There will be a screw inside holding the head on. Pull the head off the shaft, (you may need to lever it off) unscrew the shroud (the chrome bell shaped piece around the shaft) that will expose a large nut, unscrewing that with a spanner while bracing the tap by hand (a glove ain’t a bad idea in case something goes!) to reduce strain on the basin will remove the working part of the tap.
Replace the washer, either pushed on a pin or held with a nut or screw through the centre. Reassemble in reverse.
Now the bad news, the whole thing will almost certainly be stuck solid with scale.
Try soaking each bit in vinegar or descaler for a while if it will not move.
In theory the knurled nut and shroud should only be hand tight, but you may need pipe grips or gland nut pliers to remove them, wrap rag or better still something like a piece of rubber around to protect the chrome.
You may find one of those rubber kitchen discs that are for gripping tight lids will enable you to remove them without using tools.
Required,
Screwdriver, no idea what type till you see the screws they used.
Adjustable spanner, an 8” may do it but a 10” (that’s the overall length of the spanner) will be a safer bet.
Gland nut / Water pump pliers/ pipe grips, 9” or 10”. You can use these instead of the spanner on the inner nut, it’s just bad practice to use tools with teeth on nuts as it rounds them off after a few times.
Turn on water, run for a few mins to flush out any debris, fill kettle make tea and sit back to admire your work!
Good luck,
Regards,
footprints