Varnishing wood isn’t the most hardest of tasks. It helps preserve the wood from scratches, stains etc, helping prolong the life of the wood.
When varnishing wood, select a day when it is dry and warm. If it’s too hot and humid, the drying process slows down, which means dust settles on the wood. Before you start the varnishing. remove the old finish on the wood with paint stripper and a paintbrush. Then sand and clean the wood to make sure the surface is smooth. If the surface is bumpy, then the varnish will not adhere.
After the wood is dry, apply a first coat of thinned varnish using a foam brush and then let it dry overnight. After the first coat is done, sand it and wipe with a cloth to remove the dust. Then apply a regular coat of varnish, allow it to dry and coat again if you deem necessary.