When talking about ALA… it says that an obstacle free surface extends from the end of the ALA for 900m…
So the ALA is where the airplane can land… would this then be the TORA/LDA?The physical length of the runway pavement
And would the 900m at the end of the ALA be the clear way?
I can vaguely recall a question about this is the exam… I remember it threw me off… I got all confused as it talked about ALA

Suggest you download, read, and keep for reference Part 139 MOS which has the general (certified) aerodrome stuff available. CAAP 92-1 provides information for ALAs.

an obstacle free surface extends from the end of the ALA for 900m

This is what you are required to establish prior to using the ALA and is similar to the end TODA gradient to the critical obstacle available for a licenced aerodrome. It is not a case that there are no obstacles, rather such obstacles as may exist are below a required gradient.

Be VERY wary of operating from minimum standard ALAs. You are very likely only to be around a couple of hundred feet at that point ...

would this then be the TORA/LDA?

Rather TODA/LDA. TORA really has nothing to do with light aircraft. It is an aerodromes standards thing and is relevant to heavy aircraft where it can be quite important to operations and figuring out takeoff weights on the day.

The physical length of the runway pavement

Keep in mind that the original idea of ALAs was to cover operations from paddocks, not aerodromes. Gradually, many country paddock strips were upgraded and, for the light aircraft pilot, appeared to be little different to country aerodromes which were licenced. You may have a runway .. or it might just be part of the paddock.

And would the 900m at the end of the ALA be the clear way?

Absolutely not. Clearway is part of the declared TODA for licenced aerodromes and must be under the control of the aerodrome authority. Most ALAs are rather downmarket from this consideration.

I got all confused as it talked about ALA

Think about there being two classes of airfield - licenced (or certified - as in most of the entries in ERSA. Some of the more frequently used non-certified fields are in ERSA) and unlicenced (the rest - ALA). There are also military airflelds but probably you won't be concerned with these.

Unlicenced strips may be of a reasonably high standard for light aircraft, ranging down to rough paddocks. Much of my early fun flying was in and out of paddock ALAs during glider towing operations. Gliders often end up in all sorts of paddocks when the lift runs out and the pilot didn't have a useful plan to get somewhere nice. (Actually, most of those paddocks probably weren't within a bull's roar of meeting all the ALA requirements but let's not go there, shall we ?).