Adding a payment option to existing website

Requirement: To allow online payments for training courses on a website [login to view URL] This website is built in html and I don’t wish to change this. I would like a link from this to a payment page where people can see what spaces are available and book them. If it’s easier to make this go to a new website then I am okay with this. I offer 3 courses on sporadic dates throughout the year. The courses are: 1. JNCC Marine Mammal Observer (MMO) (16 spaces available) 2. BOEMRE Protected Species Observer (PSO) (16 spaces available) 3. Passive Acoustic Monitoring (PAM) (12 spaces available) ****Please note that people cannot do the second course unless they complete the first course earlier in the day ****** Therefore a person can book any of the following combinations JNCC MMO JNCC MMO/BOEMRE PSO JNCC MMO/PAM JNCC MMO/BOEMRE PSO/PAM PAM I can imagine that a booking system would look something like the attachment. This is only a suggestion. Based on the attachment - Once the space has been booked and paid for the text changes from “book this space” to “booked” I need people to be able to see how many spaces are left for each course because some people book several spaces – i.e. they will only book four spaces if they can see clearly that four spaces are left. Because the second course can only be completed if they have first done the first course – if someone chooses to only do the first course i.e. JNCC MMO only or JNCC MMO/PAM combination then one option to book the space on the BOEMRE should disappear. Sometimes I get companies book spaces and when they do this I don’t make them pay in advance – I invoice them. Therefore I will need to be able to blank out spaces on the booking page myself if a company book 4 spaces for example. I have paypal business account already set up. If someone needs a refund I need to be able to issue this easily and free up the space again on the website. For registration purposes – I need everyone booking to give me the following details in this order: Surname: First name: Company (if no company – state “freelance”) Email address: Phone number: Name to appear on certificate: They would also need to tick a box to say they have read the terms and conditions. Once they have booked I would like an automatic document to be sent to them outlining some details regarding the course. I can make this document generic to all courses so we don’t have to have a different one for each course. I would like this to be as simple as possible. It’s important that I can add a new course date easily. So I may have several courses listed for booking. Dates are not regular so I will need to add the next booking module to a page as and when I need to. I would also like to be able to change the process easily in future. This must be secure. Happy bidding! Alison Gill