How to install Plots

# I encountered the following problems when installing Plots. What should I do?
ERROR: GitError(Code:ENOTFOUND, Class:Repository, Could not find repository from
macro expansion at .\libgit2\error.jl:99 [inlined]
Base.LibGit2.GitRepo(::String) at .\libgit2\repository.jl:10
prefetch(::String, ::String, ::Array{String,1}) at .\pkg\cache.jl:41
resolve(::Dict{String,Base.Pkg.Types.VersionSet}, ::Dict{String,Dict{VersionNumb}}, ::Dict{String,Base.Pkg.Types.Fixed}, ::Dict{String,VersionNumber}, ::Set{Str
resolve(::Dict{String,Base.Pkg.Types.VersionSet}, ::Dict{String,Dict{VersionNumb}}, ::Dict{String,Base.Pkg.Types.Fixed}) at .\pkg\entry.jl:479
edit(::Function, ::String, ::Base.Pkg.Types.VersionSet, ::Vararg{Base.Pkg.Types.
(::Base.Pkg.Entry.##1#3{String,Base.Pkg.Types.VersionSet})() at .\task.jl:335
Stacktrace:
 [1] sync_end() at .\task.jl:287
 [2] macro expansion at .\task.jl:303 [inlined]
 [3] add(::String, ::Base.Pkg.Types.VersionSet) at .\pkg\entry.jl:51
 [4] (::Base.Pkg.Dir.##4#7{Array{Any,1},Base.Pkg.Entry.#add,Tuple{String}})() at
 [5] cd(::Base.Pkg.Dir.##4#7{Array{Any,1},Base.Pkg.Entry.#add,Tuple{String}}, ::
 [6] #cd#1(::Array{Any,1}, ::Function, ::Function, ::String, ::Vararg{String,N}
 [7] add(::String) at .\pkg\pkg.jl:117

I guess you tried to post a screenshot, but as a local image. Please copy the error message instead as text (quoted with backticks).

thank u very much!!!

What did you execute to get this error message?