You can install Sytist in a sub folder (yourwebsite.com/FOLDER_NAME) so the link would be something like yourwebsite.com/clients, yourwebsite.com/store, etc....
1) When connected to your website with your FTP program, create the new folder in the public folder (public_html for example) you want it to be called. Best to make it all lower case with no spaces (most servers are case sensitive).
2) Go into that folder and upload the contents of the sytist_INSTALLATION_files folder from the zip file you downloaded from your order.
3) After the files have completed uploading, go to the install page which will be yourwebsite.com/FOLDER_NAME/install/
Sytist Manual > Installation