Assuming there are images and a fair bit of data held within the site, you can be sure that the size of the upload is quite substantial. For this reason, you need a reasonably high speed connection dial-up connections can be slightly erratic over a long period of time.
By far, the easiest method would be to use a native upload feature from the host's file manager over a quick connection. If this is available, simply use it to upload the archive file across to the host server. The demo site has this facility, as shown in the next screenshot:
Notice that the file is being uploaded to the
public_html folder, because this is ...