Thank you for this question.Prune off all the dead limbs to an outward facing bud. Flexible branches and twigs that don’t snap when gently bent are alive. Sections of branches that are alive may be cut back to a lateral rather than cutting off the entire branch.Begin the structural pruning process now or wait until next spring just after the leaves open up. Do not remove more than ¼ of the live branches per year. The site from Florida explains how to do structural pruning  a young tree.https://hort.ifas.ufl.edu/woody/structural-pruning-flash.shtml Your tree should be mulched with a  a 3-4 inch layer of wood chips or shredded bark. The mulched area to a width of six feet in diameter. The mulch should be six inches away from the trunk.  If you first install overlapping thick layers of wet newspaper over this area you can kill the grass. Make sure to provide supplemental irrigation to newly planted trees and shrubs if we aren't getting a ½ inch of rain during the week. Even trees planted last year or the year before should still be provided irrigation through what is considered the establishment period. You can also use watering bags such as Gator Bags which you place around the tree and fill with water and it slowly drains out.  Please read the following site.

https://extension.umn.edu/planting-and-growing-guides/pruning-trees-and-shrubs