1. Head over to supabase.io and sign up.
2. Click on 'New Project' to create a fresh project.
3. Once it's all set up, go to the Project Dashboard.

1. In the project sidebar, find the API section.
2. Jot down the url and anon key from the Project API Keys section. You'll need these later.

1. Sign up at sendgrid.com.
2. After registering, navigate to the API Keys page.
3. Create a new API key with the right permissions and keep it safe.

1. Start a new Node.js project by running npm init -y.
2. Install the Supabase client and Axios:
   ```sh
   npm install @supabase/supabase-js axios
   ```

1. Make a new JavaScript file, maybe call it sendEmail.js.
2. Import the Supabase client and Axios:
   ```javascript
   const { createClient } = require('@supabase/supabase-js');
   const axios = require('axios');
   ```
3. Set up Supabase with your API keys:
   ```javascript
   const supabaseUrl = 'https://xyzcompany.supabase.co';
   const supabaseAnonKey = 'public-anon-key-xyz';
   const supabase = createClient(supabaseUrl, supabaseAnonKey);
   const sendGridApiKey = 'your-sendgrid-api-key';
   ```
4. Write the function to send emails:
   ```javascript
   async function sendEmail(toEmail, subject, text) {
   const emailData = {
   personalizations: [
   {
   to: [{ email: toEmail }],
   subject: subject,
   },
   ],
   from: { email: 'youremail@example.com' },
   content: [
   {
   type: 'text/plain',
   value: text,
   },
   ],
   };
   
   try {
   const response = await axios.post('https://api.sendgrid.com/v3/mail/send', emailData, {
   headers: {
   Authorization: Bearer ${sendGridApiKey},
   'Content-Type': 'application/json',
   },
   });
   console.log('Email sent successfully:', response.data);
   } catch (error) {
   console.error('Error sending email:', error.response ? error.response.data : error.message);
   }
   }
   ```
5. Export the sendEmail function if you need it elsewhere:
   ```javascript
   module.exports = sendEmail;
   ```

1. Set up a trigger in Supabase to watch for changes in your table:
   ```javascript
   const listenForChanges = async () => {
   const { data, error } = supabase
   .from('your_table')
   .on('INSERT', async payload => {
   const newRecord = payload.new;
   
   // Use the sendEmail function here
   await sendEmail(newRecord.email, 'Welcome!', 'Thank you for signing up!');
   })
   .subscribe();
   
   if (error) {
   console.error('Error setting up listener:', error.message);
   }
   };

   listenForChanges();
   ```

1. Make sure your backend service is up and running so it can listen for changes and send emails.
2. Run your script with:
   ```sh
   node sendEmail.js
   ```

And there you have it! This will link Supabase with SendGrid, so you can send emails whenever there's a new event in your database.