ERP implementation step by step: what actually happens from kickoff to go-live

An ERP implementation sounds like a big, mysterious event. It is actually a sequence of ordinary steps, each of which has a clear purpose. Here is what happens in a well-run project, what you will be asked to do in each phase, and where things usually go wrong.

Phase 1: Discovery

This is the most important phase and the one most often rushed. The implementer sits with each department and maps how work actually flows today: how a quote becomes an order, how stock arrives and leaves, how a supplier bill gets approved, how month end is closed.

The output is a written specification: which modules, which workflows, which reports, what data moves from where, what needs customising and what will use standard features. You sign it off, and it becomes the basis of a fixed quote.

Your job: make the right people available and be honest about how things work, including the messy bits. Discovery is not the time to describe the process you wish you had.

Where it goes wrong: when discovery is skipped or done by email, and the real requirements surface halfway through the build, when they are expensive to accommodate.

Phase 2: Design and configuration

The core system is set up: company details, chart of accounts, VAT, users and roles, warehouses, product categories, price lists, document templates. Any custom fields, workflows and reports are designed and agreed.

Your job: review screens and templates as they appear and say early if something is not right.

Phase 3: Build

Customisations are developed and integrations are built. In our projects this happens in two week sprints, with a demo at the end of each so you can see progress and steer. We explain the approach in agile and sprints explained.

Where it goes wrong: requirements that change every sprint. Some change is normal; constant change means discovery was incomplete.

Phase 4: Data migration and testing

Your customers, suppliers, products, price lists, open orders, stock levels and opening balances are moved into the new system. This is done at least twice: a trial migration into a test system, then the real one just before go-live.

Testing follows: your team runs real scenarios end to end. Raise a quote, convert it, pick, deliver, invoice, receive payment. Order from a supplier, receive it, match the bill. Close a month.

Your job: clean your data before migration and test properly. Our data migration guide explains what to clean and what to leave behind.

Where it goes wrong: migrating years of messy history because "we might need it", and testing with tidy examples instead of the awkward real ones.

Phase 5: Training and go-live

Each type of user is trained on their part of the system, with written guides they can refer to afterwards. Go-live is a planned switchover, usually at a month or VAT quarter boundary so opening balances are clean. The old system is kept available read-only.

The first days and weeks after go-live are the hypercare period, when the implementer is on hand to fix issues quickly.

Where it goes wrong: going live mid-period, training only one "super user" who then becomes a bottleneck, or switching off the old system before you are sure.

Phase 6: Support and improvement

After hypercare, most businesses move to a support plan covering updates, fixes and small improvements. The first few months always surface ideas for phase two, from extra modules to reports nobody thought to ask for.

How long it takes

For a small business with three to five modules and up to 30 users, the six phases typically take 6 to 10 weeks. Larger, multi-company or heavily customised projects take 12 to 20 weeks or more. We break this down by business size in how long does an ERP implementation take.

The one thing to remember

Projects fail because of people and data far more often than because of software. Give the project a lead on your side with authority, involve each department, clean the data, and test with real scenarios. Do that and the software part is the easy bit.

If you want to talk through what this would look like for your business, our free discovery call is the first step. Read about our ERP service or request a quote.

Frequently asked questions