Assuming you have explored all of the options and do need to look externally for a solution then in most cases, apart from fairly small-scale pilots, your acquisition of new technologies will be subject to formal procurement procedures.
This means that the final stage of defining what you need is to set out your requirements in an Invitation to Tender (ITT). This document requires careful preparation if you are not to waste your own and suppliers’ time on unsuitable tenders. It should give suppliers a reasonable amount of background information about your organisation and your project as well as setting out the detailed requirements specifically and clearly.
One thing that you need to think through very carefully upfront is how you will evaluate the tenders you receive. You may choose simply to accept the lowest priced tender that meets your requirements but it is more usual to define a set of criteria by which you will identify the most economically advantageous tender (a phrase often abbreviated to MEAT).
You will need to state the criteria to be used and any weightings to be applied in the ITT. If you fail to do this then, under EU regulations, you will be obliged to accept the lowest priced tender.
It may seem very early to be doing this but you really need to develop your marking system and scoring template at the same time as the ITT. You should be absolutely clear about the mapping between your stated requirements and the evaluation criteria and it would be good practice to show this in an appendix to the ITT.
It pays to discuss the criteria and weightings with a range of key stakeholders and do some modelling just to ensure there are no hostages to fortune in your marking scheme that may skew the scores in ways that would be undesirable. You should also think about who will constitute your marking panel and ensure they are fully briefed at an early stage.
If you are making a major investment and are planning some kind of evaluation or demonstration event then you need to make absolutely sure that your procurement procedure allows for this, and that your ITT is clear about the basis for shortlisting and how shortlisted suppliers will be evaluated in the subsequent phase.