To move data from SendGrid, you first need an API key. Log in to your SendGrid account, navigate to the "Settings" section, and select "API Keys." Create a new API key with the necessary permissions, such as "Read Access" to the data you wish to transfer (e.g., email activity, lists). Store this key securely as you'll use it to authenticate API requests.

Ensure your environment has the necessary libraries for interacting with SendGrid and Redis. If you're using Python, for instance, you need `requests` for HTTP requests and `redis-py` for connecting to Redis. Install them using pip:
```bash
pip install requests redis
```

Use the SendGrid API to fetch the data you need. For example, to get email activity data, make a GET request to the SendGrid Email Activity API endpoint:
```python
import requests

api_key = 'YOUR_SENDGRID_API_KEY'
headers = {
'Authorization': f'Bearer {api_key}',
'Content-Type': 'application/json'
}
response = requests.get('https://api.sendgrid.com/v3/messages', headers=headers)
data = response.json()
```
Ensure to handle pagination if your dataset is large, by checking for links to the next page in the response headers.

Depending on what your Redis instance will be used for, you may need to transform the data. This can include filtering, reformatting, or aggregating the data to match the structure your Redis database expects. For example, you might want to store only specific fields from each record.

Establish a connection to your Redis instance. Use the `redis-py` library to create a connection client:
```python
import redis

client = redis.StrictRedis(host='localhost', port=6379, db=0)
```
Replace 'localhost' and 'port' with the appropriate values for your Redis server.

With your data ready and connection established, iterate through your data and store it in Redis. For example, if storing email activity logs, you might use a hash or a list:
```python
for record in data:
email_id = record['email_id']
client.hset(f'email:{email_id}', mapping=record)
```
Choose an appropriate data structure for your use case, such as hashes for key-value pairs or lists for ordered data.

After transferring the data, ensure everything is stored correctly. Manually check a few entries in Redis to verify accuracy. Optionally, set up a script or cron job to automate this data transfer process at regular intervals if needed. Monitor both SendGrid API usage and Redis performance to avoid hitting rate limits or running into storage issues.