To find the location of an application that has been installed using Microsoft’s „Store“ you can use the taskmanager after you have opened the program in question. Expand the entry for the program (clicking on the leading „>“), right click the subentry carrying the program’s icon and select „open file location“ (or „Dateipfad öffnen“ in german). Your file explorer shoud pop up now showing the installation folder of the program with the program’s executable file highlighted.
The full „adding“ process might go like this:
Open the „sendTo“-folder in your file explorer as usual (e.g. by right clicking the „Start“-Button and then „Run“ (or „Ausführen“ in a german Windows) – in the opening dialog enter „shell:sendto“), drag the executable from the folder where it has been installed (to be found as described above) into the „sendTo“ folder holding it with the right mouse button. After releasing the button select „Create shortcut“ („Verknüpfung erstellen“) and adapt the shortcut name as desired (e.g. removing the „.exe“).