Tube journey from Heathrow to Earls Court

[FilledSoda]

I'm flying into Heathrow and need to make my way to Earls Court.
I'm clueless. I haven't left Ireland in 20 years so London Tubes are new to me.
The research I've done would suggest that a visitor's oyster card isn't necessary as I can simply use my contactless bank card, is that correct?
Can I do this on all forms of public transport?
So I get on the tube at Heathrow and I will have to change.
Does that mean I get off and stay on the platform for the correct one to come along?
Is there more than one platform?
The fares on the website show a startling variation in prices.
Is it priced on the zone?
Does anyone have a ballpark figure what that journey might cost ?
Any pointers would be great.

It's a direct tube from Heathrow to Earls Court on the Picadilly Line

Yes you can use a contactless bank card.
Get on to the Piccadilly line at Heathrow and get off at Earls Court. You shouldn't have to change.
There is more than one platform but look for the one that says 'trains to Central a London'. The destination of the train will be probably Cockfosters or Arnos Grove.
Yes it is priced according to zones. I have no idea how much it costs. The Transport for London website might be able to help you.

For a single journey if you use contactless it will cost between £1.50 & £2.80 depending whether you travel peak or off peak.

You will be travelling between zones 1-6 so if you make more than one journey you won't pay more than £11.80 per day.

Ah ha !!
So pretty straightforward.
Thank you so much for the replies.

It's so cheap.
So that's why I shouldn't get a cab.

One thing to remember is that you have to use the contact less card to swipe in at the gates when you go through the barriers, and you also need to swipe out with the same card to leave. Even if the barriers are standing open, you must swipe out! That confirms your exit point and the correct fare.

If you don't, then you'll be charged the maximum single fare. Still way cheaper than a cab, but annoying!

Thank you Squirm