Generally speaking, you'll need to remove the cassette/freewheel/block in order to get access to both sides of the wheel.
Your photo shows no bearings - its not impossible they're still in the wheel?
Suggestion - Clean the whole wheel first. Dirty stuff makes any job harder. That rim looks pretty bad.
There's a good chance you can transfer most of the nuts and spacers over, keeping the same order as in your photo. Depending on wear of the cone's bearing surface, you might use the new or old one.
Clean out all the old grease/lube from the wheel's bearing races (the cups) Use a solvent and those paper towels to make it clean.
Then put in some grease, and use it as a "mortar" to hold the bearings in place around the raceway.
Tools You need a cone spanner and a regular spanner, to tighten the cone against the locknut and hold it in position. You will require grease for the bearings, and its always a good idea to fit new bearings while its all open. The old ones might look okay but bearings are real cheap, $3-$10 a wheel.
Endgame is to have your hub assembled like this: - yours is 99% a freehub so will look like the lower photo.
Your axle broke because of the loading - notice how the ball bearings (red) are not very far out-board on the freewheel compared to the freehub? This means the axle is under a continual bending stress near where it fractured. There's a chance your new axle will do the same over time, which is why freewheel designs are relegated to the cheap end nowdays and are gone from most bikes.
Still it'll be totally rideable with a new axle.