If your TV is HD you will want an ATSC tuner rather than a converter box which is meant for older SD TVs
The digital converter box will have both AV (3 RCA) and RF outputs. You connect one to your TV and the other to the VCR.
If you get two converters you would then have the option of watching one program and recording another. In this case the TV and VCR each gets a box.
The VCR will not be able to change channels on the converter so you will have to set the channel you want to record as either the AV input or channel 3/4. You will still be able to set the timer on the VCR.
If you use the VCR for timeshifting then you could get https/www.amazon.com/Premium-Clear-Tuner-Recording-Outputs/dp/B01L9EKNPW.asp
Much more flexible and it...