If you are for the first time snyn content from myRent to TFW, you need to first open a new "slot" in TFW extranet.
Next step would be to go to the property settings-B2B connections-TFW and click on OK. There you will find "sync all"
With it will sycn all content from myRent.
If you have prolomged your TFW account for an extra year, and the content is still the same BUT you need to just send new prices. You do not need to again sync all, but just PRICE.
If you have new property pictures, or some new amenities, or some new description, or change contact details you do not need to click on sync all. You can just sync the part of content which is new and which you want to push from myRent to TFW.
You can go to property details-B2B connections-TFW - ADV and then you will have possibility just push what you need.