It is correct that there are no spaces between words in Lao script. Thus to separate words you will actually need to recognize each word you read to know where the spaces are supposed to go. It is really not as hard as it sounds. Take this example in English:
You would be able to read this even without spaces as "where - are - you - from", because your eyes recognize all 4 words. Now the equivalent in Lao:
ເຈົ້າມາແຕ່ໃສ (ເຈົ້າ - ມາ - ແຕ່ - ໃສ or transcribed jâo máa taa sai)
So to read Lao script I would say you need a decent vocabulary first.
Sentences in Lao are separated by space. Commas, semi-colon etc are not used, but question marks I often see (although I believe in the old days they used some kind of tone mark to indicate questions marks).
Hope you will continue with your Lao language studies - it is really a fun language to learn