Async download using checkboxes

I have created a WPF C# gui that should work as a multiple downloader for tools. checkboxes for each app and a download button. Could anybody help me with a startup for the download code?Very new to C# and while I googled alot I still haven't found something that works for my case. The download button should check wich of the checkboxes are checked and download the files async. Thanks in advance