Without individualizing the zones, you will need to connect the single valve you have to the master valve (M) output of your new controller.
In order to continue using the index valve you have now, you will need to introduce a delay between zones as this allows the index valve to cycle between zones. Such a delay can be configured if your M terminal is set to the Well / Pump relay (don’t worry about nomenclature, setting your unit to this setting will not actually negatively effect your setup). Here is more info on this setting and how to gain access to the delay between zones setting.
Setting the delay between zones to about 5 minutes, should allow your index valve to cycle as needed.
Your current schedule treats all of your zones the same, unfortunately you will have to continue doing so. While the old setup seems to have watered each zone for 20 minutes twice a week, you can make some use of the flex daily schedule for added water savings (which is a big point of a smart irrigation controller). Alas you will have to set all of your zones to be clones of the thirstiest zone, meaning that when everr the controller should decide to water one of your zones, it should determine that the other three zones should be watered as well. If you want to maximize the savings, and individualize the zone settings, than you will have to individualize the vales as I’ve done in the post above.
Be sure to match all of the settings, including the sprinkler head types, slope, sun exposure, etc. You will still gain additional benefits compared to your old controller from the weather forecasts and moisture tracking.
Let us know if you run into any issues. If you notice that zones got of sync with eachother (wanting to be watered on different days), you may want to check the settings and let us know.