Salesforce to Zoho Data Migration

We have a backup of all data from Salesforce and need this importing into a new (empty) Zoho CRM.

There are approx. 9.5K account and 10K contact records with a few custom fields.

We need key records (all relevant fields) for the following imported along with the specified relations between the records. Once completed, basic navigation from Contact > related Accounts > related Opportunities > related attachments/chats/notes should be possible. No development beyond this is required in this first phase.

Once we have the above main records migrated and verified the data, we will then be looking to have a follow on project to develop Zoho CRM to meet our requirements including external integrations.

The records to be migrated are as follows:

Contacts (linked to related accounts)
Accounts (linked to related contacts)
Notes / Chats (linked to related accounts / contacts / opportunites)
Opportunities (linked to related accounts / contacts)
Leads (linked to related accounts / contacts)
Attachments (linked to related accounts / contacts / opportunites)
Cases (linked to related accounts / contacts)

We are happy to answer any questions or provide further information as required.