How do I reduce my 42 Mb folder project to the minum?

I'm very new to Unity and I made with Unity 2d a simple tic tac toe game, when I build it I notice the excessive folder dimension: the project's folder is 42.2MB

• exe file is 638 KB

• UnityPlayer.dll size is 26Mb

• folder MonoBleedingEdge 6mb

• folder DATA 6mb

I chose as platform PC,Mac & Linux, used compression method LZ4HC, and stripping level medium

I don't have a clear idea of what I'm doing.

 this is my Build Report
 Uncompressed usage by category (Percentages based on user generated assets only):
 Textures               96.3 kb     0.6% 
 Meshes                 0.0 kb     0.0% 
 Animations             0.0 kb     0.0% 
 Sounds                 0.0 kb     0.0% 
 Shaders                0.0 kb     0.0% 
 Other Assets           3.8 kb     0.0% 
 Levels                 7.7 kb     0.1% 
 Scripts                1.3 mb     8.6% 
 Included DLLs          13.4 mb     90.6% 
 File headers           12.6 kb     0.1% 
 Total User Assets      14.8 mb     100.0% 
 Complete build size    59.9 mb